The Exposure Assessment Core C will provide analytical support for comprehensive assessment of lead exposures in Projects 1-4. Body burden measures will include blood lead, plasma lead, ZPP, and bone lead, representing multiple compartments for deposition of lead and widely variable rates of elimination. As an adjunct to Projects 1 and 2, measurement of total lead in soil extracts will be done to validate quantitative measures obtained separately by stable isotope determinations. For Projects 5-7, an overall assessment of organic contaminants in harbor sediments is integral to ecological studies and to in vitro utilization of these samples. Extensive characterization of organochlorines will be done in Project 5, and this Core will supplement those studies by providing analyses for PAH and TCDD, compounds that are environmentally important and that may contribute significantly to the assays to be done in Projects 6-7